Wrapping apparatus with shuttle change

ABSTRACT

In a wrapping apparatus comprising a two-part endless track surrounding a wrapping station, a shuttle for dispensing wrapping medium able to ride around the track and thereby wrap an article in said station, and a track support structure such that at least one part of the track may be moved relative to another part so as to open and close a gap between those parts, a shuttle change may be effected by providing a movable shuttle carrier in the form of a length of track, and means enabling the shuttle carrier to be inserted into and removed from a gap in the track whereby a replacement shuttle may be driven from the carrier onto the track and a spent shuttle may be driven from the track onto the carrier for removal therewith.

TECHNICAL FIELD

This invention relates to wrapping apparatus of the kind comprising adispensing shuttle, from which a web of wrapping medium is drawn, andwhich rides around an endless track and thereby orbits an article, orpart of an article, that is to be wrapped.

BACKGROUND ART

In some instances the track of such wrapping apparatus is linked with anannular or similar article to be wrapped. In such instances, the tracknecessarily comprises two parts that may be separated, to enable thetrack to be linked with the article, and then re-united to enablewrapping to proceed. One of the track parts may be hinged to the other,but, for preference, the two parts of the track have been separablebodily, to create two gaps in the track when they are separated.

In that an element of the present invention is the creation of a gap inthe track, it is particularly well adapted for application to wrappingapparatus able to link with annular articles as aforesaid.

An example of wrapping apparatus of the kind under discussion, as used,for example, to wrap coils of metal strip in plastics film or sheet, isdisclosed in the specification of our Australian patent No. 653,255.From that specification it will be apparent that the wrapping medium,having been drawn as a web from a roll of medium carried by the shuttle,follows a tortuous path within the shuttle to enable it to be tensionedand to provide a reserve of tensioned web for accommodating variationsin the rate at which the web is drawn from the shuttle.

As a result, re-loading a shuttle when all of the roll of medium isspent, or re-threading the web through the shuttle in the event of theweb breaking, are time consuming operations, so that there isconsiderable down time of the apparatus due to such operations. This isparticularly unsatisfactory if the wrapping apparatus is operating aspart of a production line that dictates the time available for thecompletion of each wrapping operation.

DISCLOSURE OF INVENTION

An object of the present invention is to reduce the down time inherentin the process of re-loading or re-threading a shuttle.

The invention consists in wrapping apparatus comprising a multi-partendless track surrounding a wrapping station, a shuttle for dispensingwrapping medium able to ride around the track and thereby wrap anarticle in said station, a track support structure operable to move atleast one part of the track relative to another part so as to open andclose at least one gap between those parts, a shuttle carrier adapted,at least when said at least one gap is less than fully open, to spansaid at least one gap as a continuation of the track thereacross,carrier support means operable to insert and remove said carrier intoand from said at least one gap, and control means controlling theoperation of the track and carrier support means; whereby a replacementshuttle may be inserted with the carrier and shunted from the carrieronto the track and a used shuttle may be shunted from the track onto thecarrier and removed with the carrier.

The invention further comprises a method of reloading a wrappingapparatus of the kind comprising an endless track and a shuttle fordispensing wrapping medium able to ride around said track, comprisingthe steps of providing a loaded shuttle on a shuttle carrier, creating agap in said track, inserting said shuttle carrier into said gap,shunting a spent or partly spent shuttle from said track onto saidcarrier, shunting said loaded shuttle from said carrier onto said track,removing said carrier from said gap, and closing said gap.

BRIEF DESCRIPTION OF THE DRAWINGS

By way of example, a presently preferred embodiment of the abovedescribed invention is described in more detail hereinafter withreference to the accompanying drawings.

FIG. 1 is and end elevation of a wrapping apparatus according to theinvention with some parts cut away and other movable parts shown in fullline in an "on-line" position as during a wrapping operation and inbroken line in an "off-line" position as during a shuttle changeoperation.

FIG. 2 is a sectional side elevation of the apparatus of FIG. 1 taken online 2--2 of that figure, with movable track parts shown in full line ina "track closed" position and in broken line in a "track open" position.

FIG. 3 is a view similar to FIG. 2 taken on line 3--3 of FIG. 1.

FIG. 4 is a longitudinal sectional elevation of a loaded shuttle, beinga component of the apparatus of FIG. 1 drawn to a larger scale.

FIG. 5 is a diagrammatic cut away perspective view of the shuttle ofFIG. 4 showing its engagement with a track and power supply means.

FIG. 6 is a sectional view taken on line 6--6 of FIG. 2 showing a spacerand its support means in the stand-by position drawn to a larger scale.

FIG. 7 is a view similar to FIG. 6 showing the spacer and its supportmeans in the operative position.

FIG. 8 is a perspective view of the spacer and spacer support meansappearing in FIGS. 6 and 7.

FIG. 9 is a sectional view taken on line 9--9 of FIG. 1, showing ashuttle carrier drawn to a larger scale.

FIG. 10 is a sectional view taken on line 10--10 of FIG. 9.

FIG. 11 is a perspective view of the shuttle carrier appearing in FIGS.9 and 10.

BEST MODE OF CARRYING OUT THE INVENTION

According to the preferred embodiment described in the specification ofour above mentioned Australian patent the movable track part was hingedto the other part, but in the exemplary embodiment of the invention nowbeing described, a shuffle track 12 being the rail or like componentdirectly engaged by a dispensing shuttle 13 and which determines thepath of the shuttle, comprises two bodily separable track parts 12A and12B respectively, each of which is a mirror image of the other. Thetrack parts 12A and 12B are generally U shaped, each comprising an upperlimb 14, a lower limb 15 and smoothly curved crotch portions connectingthe limbs together. The upper limbs 14 are in alignment and projecttowards each other. The same applies to the lower limbs 15. This enablesa normal wrapping operation to proceed while the track 12 is in the"track closed" position wherein the free ends of the U-limbs of one partof the track abut those of the other, to form a continuous loop, asshown in full line in FIG. 2.

For preference, the track parts 12A and 12B are disposed so that thecommon plane in which all four limbs lie is a vertical plane.

The shuttle track 12 is supported or defined by a rigid track supportstructure. In the present instance the track support structure is alsoformed as two separate parts 16A and 16B. The parts 16A and 16B of thetrack support structure depend from an overhead beam 17 and are securedthereto in a manner permitting each of them to be moved to and fro alongthe beam into "track open" and "track closed" positions respectively.

In the present instance the beam 17 is a hollow box section withprojecting flanges 18 extending along its bottom corners, and thoseflanges are engaged by C sectioned slides 19 fixed to the parts 16A and16B of the track support structure. The parts 16A and 16B of the tracksupport structure may be moved along the beam 17 by any appropriatemotor means or linear actuator, in the present instance the aforesaidmovement is effected by double acting hydraulic cylinders 20 mountedwithin the beam 17. Those cylinders 20 are connected at their adjacentends to a central anchorage 21 and at their opposite ends to brackets 22extending from the respective track support structure parts 16A and 16Bthrough slots in the lower wall of the beam 17. For preference thebrackets 22 are respectively connected to opposite flights of an endlessloop of chain (not shown) trained around sprockets at each end of thebeam 17, so as to ensure that as the track support structure parts 16Aand 16B move to and fro they always remain equidistant from the centrepoint of the beam 17.

Thus, both track parts 12A and 12B are movable to and fro so as to openand close gaps between the free ends of their upper limbs 14 and theirlower limbs 15, but it will be appreciated that in other embodiments onepart may be stationary, so that movement of the track parts between the"track open" and "track closed" positions is then effected by movementof one part only.

For preference the overhead beam 17, and therefore the track supportstructure as a whole, is movable laterally, that is to say in thehorizontal direction perpendicular to the length dimension of the beam17, between "on-line" and "off-line" positions, as may best be seen fromFIG. 1. To that end the beam 17 itself may be supported below lateraltraversing means, comprising in this instance a fabricated bridgestructure 23, similar to that of a conventional workshop travellingcrane, comprising a girder 24 extending between bogies 25, adapted todrive, or be driven, along elevated rails 26 extending along oppositesides of a personnel exclusion zone within which wrapping takes place.

The bogies 25 may be driven as aforesaid by any conventional motoriseddrive means or linear actuator. In the present instance the lateraltraverse drive means comprise a reversible gear motor 34 connected by atransmission chain 35 mounted upon the girder 24. The shaft 36 hassprockets 37 engaged with a chains 38 extending tightly from respectiveend anchorages 39 near each end of the rails 26. The chains 38 extendabout guide sprockets 139 on the bogies 25. The chains 38 thus functionas stationary racks and rotation of the motor 34 causes the bogies 25 totraverse the rails 26.

Each of the track supporting structure parts 16A and 16B comprises avertical plate 27 having a profiled edge conforming with that part ofthe path of the shuttle defined by the part. That profiled edge may havea relatively narrow edge flange 28 (see FIGS. 4 and 5), which togetherwith the adjacent margin of the plate 27 constitutes the part of theT-sectioned track 12 defined by said each structure part. Alternatively,a separable T-sectioned rail may be affixed to the profiled edge of theplate 27.

The remaining edges of the plates 27 may be provided with stiffeningedge flanges, including relatively broad top flanges 29 extending alonga straight upper edge of the plate.

Those top flanges 29 lie parallel to and closely adjacent the bottomsurface of the overhead beam 17. They may carry the slides 19, or theymay engage alternative guide means fixed on the beam 17, providing forthe mentioned movement of the track structure parts 16A and 16B betweenthe "track open" and "track closed" positions.

The upper limbs 14 have somewhat curved profiled edges, to provide anendless track having an upwardly arched, upper flight, when the trackstructure parts 16A and 16B are brought together in the "track closed"position, but the lower limbs 15 are preferably straight, and extend asrelatively shallow cantilever beams from the respective crotch portions.This provides a relatively long and clear lower flight of that endlesstrack that is adapted to extend through the bore of an annular articleand leave clearance for the passage of a shuttle 13 through that bore.

For preference the apparatus comprises elevator means whereby thealtitude of the track 12 may be adjusted. In the present instance thismay be achieved, for example, by raising and lowering the overhead beam17 relative to the girder 24. To that end, the ends of the beam 17 maybe furnished with cross-head bearings 30 engaging vertical guides 31near each end of the girder 24, to enable controlled vertical movementunder the influence of load bearing linear actuators of one kind oranother. In the present instance that movement is effected by anhydraulic cylinder 32 within the girder 24 connected by chains 33extending over strategically placed sprockets to the ends of the beam17. The cylinder 32 lifts the beam 17. The weight of the beam and trackstructure is sufficient to lower it, although, for preference, thehydraulic cylinder is double acting to enable it to control the loweringspeed.

The illustrated wrapping apparatus further comprises a workpiecesupport, preferably comprising two, parallel, horizontal rollers 40, ofwhich at least one is powered, disposed one each side of a heavy dutyconveyor comprising, in this instance, an endless train of smallcarriages 41. The rollers 40 are mounted on hydraulic jacks 42 and maybe raised to lift and support a heavy cylindrical workpiece, such as acoil 43 of steel strip or the like, carried by the conveyor into awrapping station coinciding with the location of the rollers 40. Afterthe article is wrapped the rollers 41 may be lowered to re-seat thearticle on the conveyor for exit and replacement by the next article tobe wrapped. The rollers support and rotate the article as wrappingproceeds. When the article is being brought into or taken away from thewrapping station, the track structure is located in the "off-line"position, as will be more fully described below.

In other embodiments the workpiece support may be in the form of acarriage able to travel transversely of the working portion of track,but, for preference, the workpiece support is stationary and the trackis transversely movable as in the illustrated embodiment, wherein themovement of the track relative to the workpiece support (as needed topermit the emplacement and removal of a workpiece and the linking of itwith the track), is effected by transverse movement of the bogies 25 andgirder 24 along the elevated rails 26 between the "on-line" and"off-line" positions.

Thus, assuming the girder 24 is in the "off-line" position and the trackstructure parts are in the "track open" position, a coil of metal stripor other article may be positioned for wrapping by placing it upon theconveyor at a point remote from the apparatus, operating the conveyor tobring the coil into the wrapping station, lifting it on the rollers 40,driving the girder 24 into the "on-line" position, if need be, adjustingthe altitude of the overhead beam 17 to bring the lower U-limbs 15 ofthe track parts into alignment with the bore of the article, bringingthe track structure parts into the "track closed" position, so that thearticle then encircles the lower flight of the then endless track 12,activating the shuttle to wrap the article, then after wrapping iscompleted, shifting the track structure parts 16A and 16B along theoverhead beam 17 to their open positions so as to separate the trackparts, and driving the girder 24 transversely into the "off-line"position, in readiness for the next operation, and removing the wrappedarticle.

The adjustment of the altitude of the beam 17 is preferably automaticand to that end a distance measuring transceiver 44 may be positionedabove the conveyor to respond to monitor the incoming coil and send anappropriate signal to the control means of the apparatus.

Motorised shuttles 13 are provided, each of which is adapted to rideupon the T-sectioned track. To this end, each shuttle 13 may be providedwith four sets of track wheels 45, each set comprising three wheelspositioned to contact the side faces and an edge face respectively ofthe head flange 28 of the T-sectioned track. The shuttle 13 may furthercomprise a toothed driving wheel 46 engaging a rack 47 extending alongflange 28, and a motor 48 and a power transmission for rotation of thedriving wheel 46. The shuttle 13 may further comprise wiper contacts 49adapted to slide upon power supply conductor rails 50 mounted on the web27 of the T-sectioned track, for energising the shuttle motor 48.

The shuttle 13 carries a roll 51 of wrapping medium, for example,stretch wrap plastics film, and, in preferred instances, conventionaltensioning, prestretching, braking and accumulator means 52 for a web ofmedium drawn from the spool.

The wrapping apparatus may be manually controlled, but for preference,it operates automatically under the control of a programmable logiccontroller (PLC).

The PLC not only controls the drives to the major mechanical componentsof the apparatus, but also the operation of the shuttle, via control ofthe power supply to the conductor rails 50, and ancillary components,such as a web hot wire cutter adjacent a web holder device 53 forgripping the otherwise free end of the web of wrapping medium extendingfrom the shuttle at the commencement of wrapping, and for severing theweb when a wrapping operation is finished, and, in the present instance,the operation of the shuttle change equipment that is characteristic ofthe invention.

The present invention requires track support means such that at leastone part of the track is movable relative to another part so as to openand close a gap between those parts for the purpose of shuttle changing.In the present instance this requires no more than appropriate controlfor that purpose of the positions of the track structure parts 16A and16B on the overhead beam 17.

Likewise in other wrapping apparatus wherein the track is linkable withthe article to be wrapped, it requires no more than control of whatevermechanism that may be provided for separating the track parts to allowlinking to be effected.

The invention also requires a shuttle carrier adapted to be insertedinto the track as a temporary part thereof. More specifically, in thepresent instance, the inserted shuttle carrier is positioned between theends of the lower limbs 15 of the track parts 12A and 12B, so as tobecome a part of an extended lower flight of the endless track 12.

Thus the preferred shuttle carrier 54 may comprise a short length ofT-sectioned track 55, complete with conductor rails 56 and rack 57,similar to that of the main track 12 itself. The carrier 54 may beprovided with end formations, and conductor rails with end contacts, thesame as those provided at the ends of the limbs 15 of the main track toensure correct register with the mating part and continuity of powersupply from one part to the other.

However the carrier conductor rails 56 are preferably divided into twoparts. Those parts are separated or insulated from each other at 58, ator near the mid-length of the carrier. Thus the carrier may be said tohave a front end part 54A and a back end part 54B, that aredistinguishable one from the other in that the conductor rails 56 ofeach part are independently energisable.

Also it is preferable for the rack 57 of the carrier to be retractable,so as to enable it to be disengaged from the driving wheel 46 of ashuttle resting on it. To that end the rack 57 is mounted independentlyof the length of track 55 on hydraulic actuators 59. This facilitatesmanual movement of a shuttle on the carrier when in its standbyposition, as may be desired then to facilitate manual movement of ashuttle from one carrier part to the other.

For preference, a spacer 60, being a length of the T-sectioned tracksimilar to that of the carrier 54, but with continuous conductor rails,is also provided for insertion between the ends of the upper limbs 14 ofthe main track, so as to maintain the endless nature of the extendedtrack.

The carrier 54 may be mounted on a transporter truck 61 able to bedriven to and fro on carrier rails 62 by an under floor linear actuator63 (preferably a so called rodless cylinder) for movement from a standbyposition clear of the exclusion zone to a loading position where it iswithin the exclusion zone but clear of the workpiece support and anyarticle likely to be on it.

When in the loading position the carrier 54 is aligned with the shuttletrack 12 when in its off-line position, is parallel to the lower tracklimbs 15 and at an altitude within the range of altitudes available tothose limbs.

The spacer 60 may be mounted on a swinging bracket 64 hinged to one sideof the overhead beam 17. That bracket may be swung, by one or morelinear actuators 65 pivoted at one end to the beam 17 and at the otherend to the bracket 64, from a standby position (as seen in FIG. 6) wherethe spacer 60 is clear of the upper flight of the track 12 to a loadingposition (as seen in FIGS. 7 and 8) where the spacer 60 is in alignmentwith, and positioned between, the upper limbs 14 of the main track. Itis, of course, essential that the gap between the two track parts isfully open to enable the spacer 60 to enter its loading position.

The control means governing the operation of the illustrated embodimentof the invention, and that operation itself, may now be described.

The reasons for which a film dispensing shuttle 13 may need to bechanged can vary, but predominantly a change will be required for one oranother of the following main reasons:

(a) the operator has detected a minor fault or suspects same within ashuttle and wishes to take the shuttle out of service for inspectionand/or repair,

(b) the routine maintenance of a shuttle is due and that shuttle may beremoved to carry out such maintenance,

(c) the shuttle is spent, that is to say, the roll of wrapping mediumonboard the shuttle has run out and therefore the apparatus has to bereloaded, which, in accordance with the invention, is effected byreplacing the spent shuttle with one which is already primed with a newroll of wrapping medium, or

(d) the web of wrapping medium has broken or become detached during awrapping cycle (generally referred to as a "tear-off") and it may besimpler to perform a shuttle change and then re-commence the cyclerather than to rectify the tear-off problem and manually "re-thread" theweb through the partly spent shuttle.

Whatever reasons determine the need for a shuttle change to beinitiated, such a change may be ordered either by way of the operatorusing the machine control panel in the cases of a, b, c & d, or fullyautomatically in the cases of c & d.

In those latter cases, automatic initiation of a shuttle change may betriggered by a status sensor responsive to loss of tension in the webfor any reason (including apparent loss of tension due to absence of theweb). The status sensor may generate a signal for transmission to thePLC, or it may be a passive unit adapted to be monitored or interrogatedby the PLC, such that the PLC may initiate a shuttle change on detectinga change in the state or condition of the sensor.

In the present instance the shuttle 13 includes accumulator means tohold a varying length of tensioned web to accommodate variations in therate at which the web is drawn from the shuttle. Those accumulator meansinclude rolls 66 which move to and fro to take up or let out the web,and it is convenient to utilise that movement to determine the presenceor absence of tensioned web. If the accumulator parts rest in the "webaccumulated" position for any length of time greater than the durationwhich may be normally attained during the wrapping process, then it maybe deduced that the web has broken or that the roll of wrapping mediumis exhausted.

Thus, the status sensor may be a switch mounted strategically upon theshuttle so that when the moving accumulator components are positioned inthe "web accumulated" position, then the switch is caused to beactivated. Though many conventional types of switching device could beutilised, the preferred switch is a mechanically activated electricallimit switch or micro switch with normally open electrical contacts.When the moving accumulator components are resting in the "webaccumulated position" the electrical switch contacts are closed, therebycompleting an electrical circuit which, in turn, provides an input tothe PLC.

The status sensor switch may be connected to the PLC via a dedicated oneof the conductor rails 50 and an associated wiper contact 49.

However, the provision of conductor rails around the track additional tothose providing power to the shuttle motor, is inconvenient, and a morepreferred method of transferring the switching signal from the shuttleto the PLC is by way of a radio link. Thus, a miniature radio frequencytransmitter controlled by the sensor switch, and capable of transmittinga signal to a receiver located in close proximity to the moving shuttle,may replace a "hard-wired" electrical link. The same switch arrangementas previously described may still be utilised on the shuttle, howeverwhen the contacts of the switch are closed, the miniature transmitter isenergised and in turn transmits a radio frequency signal to the receiverfor a duration which corresponds with the length of time for which theswitch contacts are closed. The receiver, which is wired to the PLC,subsequently provides a relay output signal which corresponds to theswitching duration's occurring on board the shuttle. These signals areconditioned and monitored by the PLC, and if the duration of the signalexceeds that which is normal for the wrapping cycle, then this will bedetected and the PLC will either initiate a shuttle change procedure, orraise the appropriate alarm, or initiate any desired string ofprocedures as programmed into the PLC.

In other embodiments similar signalling and control arrangements may beused wherein the signal is transmitted by devices using radiations otherthan radio frequency electro-magnetic radiation, for example infra-red,ultra-sonic, laser or other light energy.

On detecting that a web tear off or run out has occurred, the PLC maycause a display change on an operator's video monitor to notify theoperator of an alarm situation. Simultaneously a "shuttle return topark" procedure is initiated which interrupts the wrapping cycle, slowsthe shuttle travel to "jog" speed, and drives it to a predetermined parkposition on the track prior to stopping. Arrival of the shuttle at thepark position may be indicated to the PLC by a proximity sensor 67adjacent the track at that position.

The aforesaid "jog" speed may be determined by reducing the frequency ofthe power supply to the shuttle motor 48.

The video display alarm may be accompanied by an audible alarm ifpreferred. The video monitor is caused to display an alarm message,which advises the operator that a film tear off or run-out has occurred,and also preferably offers a two choice menu from which the operator mayselect. Those choices are (a) "Continue Wrapping Cycle", which willallow the operator to manually correct the problem which has occurredonboard the shuttle and then re-commence wrapping, if this option isselected, or (b) "Initiate Shuttle Change", which will commence anautomatic shuttle change sequence if selected by the operator.

Alternatively, the control means could be programmed to initiate ashuttle change forthwith, that is without need of a decision or choicefrom the operator.

Be that as it may, when the PLC initiates a shuttle change it issuescommands which cause the following sequence of events to occur:

the spent, or partly spent, shuttle 13 to be replaced is driven to, andhalted in, the park position,

the cylinders 20 are then activated to cause the track structure parts16A and 16B to move to the track open position, thereby creating gaps inthe upper and lower flights of the track 12, and withdrawing the lowertrack limbs 15 clear of the article 43 being wrapped,

the girder 24 is then traversed laterally to the off-line positionwherein the track structure is situated to one side of and spaced fromthe workpiece support rollers 40,

the overhead beam 17 is then raised or lowered to bring the track limbsto a predetermined loading altitude,

the linear actuator 63 is then activated to bring the carriertransporter truck 61 and the carrier 54, with a previously loadedshuttle on a front end portion thereof, from its standby to its loadingposition between, and in alignment with, the lower track limbs 15,

the spacer bracket linear actuators 65 are activated to bring the spacer60 from its standby to its loading position, between and in line withthe upper track limbs 14,

the cylinders 20 are again activated to bring the track parts togetherto the extent that they abut the carrier and spacer to form an extendedendless track,

the track conductor rails 50 and those of the back end portion of thecarrier 54 are energised so that the spent or partly spent shuttle iscaused to travel at jog speed until it is positioned on the vacant backend portion of the carrier 54, where it is halted,

the track conductor rails 50 and those of the front end portion of thecarrier 54 are then energised to cause a loaded shuttle positioned onthe front end portion of the carrier, to travel at jog speed until itreaches the park position on the track, and then halt,

that movement of the loaded shuttle causes a web of wrapping material tobe drawn from it (the free end of the roll having been previouslysecured to a web holder 68 on the transporter truck 61 when the shuttlewas loaded therewith) and the web holder 53 intercepts that web takeshold of same and its cutter is activated (as it is at the end of anormal wrapping operation) so as to sever the web between the loadedshuttle and the carrier while maintaining a hold onto the end of the webextending from the shuttle,

the cylinders 20 are then re-activated to take the track structure partsin to the track open position, the carrier transporter truck 61 andspacer bracket 64 are returned to their standby positions, the motor 34is energised to bring the girder 24 to the on-line position, cylinder 32is actuated to bring the track parts to the correct wrapping altitude,the cylinders 20 are activated to bring the track parts together toclose the gaps therebetween, with the lower limbs 15 then extendingthrough the bore of the article 43 being wrapped, and the wrapping cycleis re-commenced.

Finally the operator may reload the spent shuttle with a fresh roll ofwrapping medium and move it to the front end portion of the carrier inreadiness for the next shuttle replacement operation.

I claim:
 1. A wrapping apparatus comprising:a multi-part endless tracksurrounding a wrapping station; a first shuttle and a second shuttleeach adapted to have on board a supply of wrapping medium and eachincluding means for dispensing said wrapping medium; each said shuttlebeing able to ride around the track and thereby wrap an article at saidstation; a track support structure including separation means for movingat least one part of the track relative to another part to open andclose at least one gap between said parts; a shuttle carrier means forspanning said at least one gap, at least when said at least one gap isless than fully open, to thereby span said at least one gap as acontinuation of the track thereacross; shuttle carrier support means forinserting and removing said carrier into and from said at least one gap;and control means for controlling movement of the track supportstructure, shuttle carrier and carrier support means; said first shuttlewhen located on said track being exchangeable for said second shuttlewhen located on said shuttle carrier and vice versa by operation of saidcontrol means.
 2. Wrapping apparatus according to claim 1 wherein theseparation means of the track support structure is operable to open andclose a second gap, said wrapping apparatus further comprising a spaceradapted to span said second gap at least when said second gap is lessthan fully open, said spacer spanning said second gap as a continuationof the track and spacer support means for inserting and removing saidspacer from said second gap.
 3. Wrapping apparatus according to claim 1wherein each shuttle is electrically driven and is movable under thecontrol of said control means.
 4. Wrapping apparatus according to claim1 further comprising lateral traversing means for shifting said tracksupport structure and the track between an on-line position wherein thetrack coincides with the wrapping station and an off-line positionspaced laterally to one side of said wrapping station.
 5. Wrappingapparatus according to claim 4 wherein said lateral traversing meanscomprises a travelling bridge from which said track support structure issuspended.
 6. Wrapping apparatus according to claim 5 wherein saidlateral traversing means is operable under the control of said controlmeans.
 7. Wrapping apparatus according to claim 1 further comprisingelevator means for raising and lowering said track support structure andthe track relative to said wrapping station.
 8. Wrapping apparatusaccording to claim 7 wherein said elevator means is operable under thecontrol of said control means.
 9. Wrapping apparatus according to claim8 wherein said control means includes a distance measuring transceiverto monitor the height of an incoming article to be wrapped as it iscarried into said wrapping station.
 10. Wrapping apparatus according toclaim 1 wherein said carrier support means comprises a carriage, guiderails for said carriage and means for moving said carriage along saidrails.
 11. Wrapping apparatus according to claim 10 wherein said meansto move said carriage comprises a linear actuator.
 12. Wrappingapparatus according to claim 10 wherein said means for moving saidcarriage is operable under the control of said control means. 13.Wrapping apparatus according to claim 2 wherein said spacer supportmeans is operable under the control of said control means.
 14. Wrappingapparatus according to claim 1 further comprising load support means forthe rotational support of a cylindrical article in said wrappingstation.
 15. Wrapping apparatus according to claim 14 further comprisinga conveyor for the transport of an article to be wrapped through theapparatus and wherein the load support means includes jacking means forlifting the article from said conveyor into the wrapping station andthereafter lowering the wrapped article onto the conveyor.
 16. Wrappingapparatus according to claim 15 wherein said jacking means is operableunder the control of said control means.
 17. Wrapping apparatuscomprising a two part endless track surrounding a wrapping station,first and second electrically driven shuttles for dispensing wrappingmedium, said shuttles being able to ride around the track and therebywrap an article in said station, a track support structure includingseparation means for moving at least one part of the track relative toanother part to open and close first and second gaps between the partsof said track, a shuttle carrier incorporating means for spanning saidfirst gap as a continuation of the track thereacross, shuttle carriersupport means for inserting and removing said carrier into said firstgap, a spacer adapted to span said second gap at least when said secondgap is less than fully open, spacer support means for inserting andremoving said spacer from said second gap, lateral traversing means forshifting said track support structure and the track between an on-lineposition wherein the track coincides with the wrapping station and anoff-line position spaced laterally to one side of said wrapping station,elevator means for raising and lowering said track support structure andthe track relative to said wrapping station, load support means for therotational support of a cylindrical article in said wrapping station, aconveyor for the transport of an article to be wrapped through theapparatus, jacking means for lifting the article from the conveyor intothe wrapping station and thereafter lower the wrapped article onto theconveyor, and programmable control means for controlling the movement ofsaid wrapping apparatus to exchange said first shuttle when located onsaid track for said second shuttle when located on said shuttle carrier,said first shuttle being driven from the track onto the carrier and saidsecond shuttle being driven from the carrier onto the track when saidshuttle carrier and said spacer are spanning the first and second gapsrespectively.
 18. A method of reloading a wrapping apparatus of the kindcomprising an endless track having a plurality of parts and a shuttlefor dispensing wrapping medium and able to ride around said track,comprising the steps of providing a loaded shuttle on a shuttle carrier,moving at least one part of said track to open a gap in said track,inserting a shuttle carrier into said gap to close said gap with saidshuttle carrier, moving a spent or partly spent shuttle from said trackonto said shuttle carrier, moving said loaded shuttle from said carrieronto said track, removing said shuttle carrier from said gap, andclosing said gap.
 19. A wrapping apparatus comprising a multi-partendless track surrounding a wrapping station;a first shuttle and asecond shuttle each adapted to have on board a supply of wrapping mediumand each including means for dispensing said wrapping medium, each saidshuttle being able to ride around the track and thereby wrap an articleat said station; a track support structure including separation meansfor moving at least one part of the track to another to open and closetwo gaps between those parts; a shuttle carrier including means forspanning a first gap at least when said first gap is less than fullyopen to thereby span said first gap as a continuation of the trackthereacross; a shuttle carrier support means including means forinserting and removing said carrier into and from said first gap; aspacer adapted to span said second gap at least when said second gap isless than fully open, said spacer spanning said second gap as acontinuation of the track; spacer support including means for insertingand removing said spacer into and from said second gap; and controlmeans controlling movement of the track support structure, shuttlecarrier, carrier support means, spacer and spacer support; said firstshuttle located on said track being exchangeable for said second shuttlewhen located on said shuttle carrier and vice versa by operation of saidcontrol means.
 20. The wrapping apparatus according to claim 19 whereinsaid spacer support is operable under the control of said control means.